Variable-speed and reversing mechanism.



No. 775,647. PATBNTED NOV. 22, 1904.

. E'. 0. FARWELL. VARIABLE SPEED AND REVERSING MECHANISM.

APPLICATION FILED FEB. 2, 1904.

N0 MODEL. 2SHBETS-SHBET 1.

@meute/c l? @GMM/W atto/Mam 6 No. 775,647. PATENTED NOV. 22, 1904. E. 0.EAEWELL. VARIABLE SPEED AND REVEESING MEGEANISM.

I APPLICATION FILED FEB. 2, 1904. y N0 MODEL. 2 SHEETS-SHEET 2.

UNITED STATES- Patented November 22, 1904.

PATENT OEEICE.

FAY O. FARWELL, OF DUBUQUE, IOWA, ASSIGNOR OF ONE-HALF TO THE ADAMSCOMPANY, OF DUBUQUE, IOWA.

VARIABLE-SPEED AND REVERSING NIECHANISNI.

SPECIFICATION forming part of Letters Patent No. 775,647, dated November22, 1904. Application filed February 2, i904. Serial No. 191,703. (Nomodel.)

To @ZZ whom it may concern:

Be it known that I, FAY O. FARWELL, a citizen of the United States,residing in the city and county of Dubuque, State of Iowa, have inventedcertain new and useful Improvements in Variable-Speed and ReversingMechanism; and I do hereby declare the following to bea full, clear, andexact description of the invention, such as will enable others skilledin the art to which it appertains to make and use the same.

My invention relates to variable-speed and reversing mechanism, and hasfor itsobject to provide mechanism for varying the speed and directionof rotation of motor-vehicles, machine-tools, and the like in which asmooth, positive, and gradually increasing or decreasing motion ineither the forward or reverse direction is desired, said mechanism beingpositive in its driving effect, simple in construction, and requiring nohigh degree of skill on the part of the operator.

To this end the invention consists, essentially, of a driving memberconnected to any suitable source of power-such as a gas-engine or asteam-engine, a driven member, preferably revolving around the same aXisas the driving member, from which driven member the power is taken atVariable speed and direction of motion, a worm-gearing carried by thedriving and driven members, respectively, and means -for varying thespeed of the worm-gearingwhereby the speed and direction of rotation ofthe driven member is regulated.

My invention is illustrated in the accompanying drawings, in Whioh-Figure lis a perspective view of a preferred form of my device. Fig. 2is a longitudinal sectional elevation thereof. Fig. 3 is a section online X X of Fig. 2. Fig. 4 shows a modified form of the variable-speedworm# Fig. 5 shows another controlling device.

Fig. 6 illustrates modification of said device.

a still further modification of the apparatus, and Fig. 7 is afragmentary view showing the revoluble frame and the mode of mountingthe gearing therein.

Referring to Figs. l, 2, and 3 of the drawings, c indicates the drivingmember or shaft,

joint-yoke la.

which is actuated-from any suitable source of power-as, for example, asteam-engine or a gas-engine. Surrounding this shaft and free to revolvethereon is a frame or casing Z, which is secured to stub-shaft 52,designated the driven member, from which power and motion may be takenby any suitable means-such as ordinary toothed gearing, a belt engagingsaid casing a chain from the sprocket 7L, or by a knuckle-joint andflexible shaft from the (Shown in Fig. l.) It is to be observed that thedesignation driven member as applied to the' casing and its connectedshaft Z22 is merely relative, and in the event of connecting the sourceof power to these parts instead of the primary shaft e, hereinbeforereferred to, the relation of driving and driven members wouldnecessarily be reversed.

Secured to the shaft c is a worm-wheel a', which necessarily partakes ofthe rotary motion of said shaft. Journaled in the frame or casing I) inproper relation to mesh with the Worm-wheel a aforesaid are two worms bwhich in addition to a motion of rotation about their axes partake ofany rotary motion imparted to said casing. Loosely mounted upon theshaft a and within the casing bis a bevel-wheel c, which is connected bya suitable hollow shaft ai with a bevel-pinion f. Mounted on suitablestuds in the frame or casing b are two bevel-pinions c c', meshing Withthe bevel-gear c, and secured to the respective studs carrying thebevel-pinions c c are gear-wheels c2 c2, meshing with pinions c3 c3 onthe shafts of the respective Worms t. A friction-disk e is secured-tothe shaft a adjacent to bevel-pinion f and is engaged by afriction-Wheel d', whichD isI slidably mounted upon a shaft cl2 toengage said friction-disk e at different distances from the center ofsaid disk, so that as the latter revolves with the shaft a the wheel elwill have a variable speed imparted to it. Secured to the shaft cl2 is abevel-gear g, meshing with the pinion f, and thereby serving to drivethe worms t through the gear-train thus completed. It will be seen,therefore, that the speed of rotation of the worms t upon their own axeswill be dependrevolution or in the reverse direction.

ent upon the position of the friction-wheel d with respect to thefriction-disk e.A

It is to be noted that the angle of the threads of the worm is such thatthe latter is self-locking and that therefore any pressure brought tobear upon these threads or teeth by the engaging teeth of the wormwheela' will, while it has a tendency to turn the worm, be ineffective to doso, and if the worm-gearing were not otherwise operated it would merelyhave the effect of connecting casing b and its shaft b2 to thedriving-shaft a, so that any motion imparted to the latter would betransmitted directly to the driven shaft. If, however, an independentrotation be applied to the worm it will have the effect of accelerating,retarding, reversing, or stopping the motion of the driven shaft.

Assuming that the driving member t revolves in the direction indicatedby the arrow in Fig.- 3 at a speed, say, of one hundred revolutions perminute, the worm-wheel a would of course revolve at the same speed.Assuming also that the worm-wheel has sixteen teeth and that the wormZJ' khas a double thread, said worm will revolve eighttimes as fast asthe worm-wheel if it were independently driven. Now if through themedium of the several bevel-gears and spur-gears g, f, c, c', c2, and c3the worm Z1 be driven eight times as fast as the driving member a andcorrespondingly the worm-wheel a7 it will be seen that the worm willrevolve idly in the worm-wheel, having no tendency to creep around thelatter either in the direction of Hence the casing and driven ,shaft Z22will remain stationary. This condition will obtain whenever thefriction-wheel l is brought into contact with the friction-disk e atsuch point that its speed is suflicient to drive the worrns eight timesas fast as the driving-shaft arevolves. If, however, the friction-rollerd is moved into contact with the friction-disk e nearer its center, thespeed of rotation of the worm will be diminished below eight times thatof the shaft a, and the worm-wheel and eworm oget er w1 e casing an th th th th b d the driven shaft b2, will revolve in the same direction asthe driving member-viz., a forward direction. As the friction roller ismoved still farther toward the center and the speed of rotation of theworm is still more reduced the casing and driven member will revolvefaster in a forward direction until when the bevel-gear c is driven atthe same speed as the worm-wheel a the driven member b2 will revolve atits maximum speed, the worm and the gearing which connects thebevel-gear c therewith will cease to revolve around their respectiveaxes, and the whole planetary system -inclosed in the casing willrevolve as a unit. Conversely, if the speed of the worm were increasedbeyond eight hundred revolutions per minute or more than eight ,times asfast as shaft a it will be apparent that the worm will move around theworm-wheel in a direction opposite that of the revolution of said wheel,and thereby cause the casing b and driven shaft b2 torevolve also in theopposite or reverse direction. This change of direction of rotation ofthe driven member is produced by moving the friction-wheel d toward theedge of the friction-disk beyond the point where it produced no motionof the driven parts, and accordingly by adjusting the position of saidfrictionwheel beyond this point the speed of the driven member in itsreverse motion may be varied at will.

It will be noted that the various modiications involve only colorabledepartures from the form of the mechanism shown in Figs. l to 3. In Fig.4C, for example, the frictiondisk e is not mounted upon thedriving-shaft ce, but is geared thereto, while the frictionwheel d ismounted directly upon the sleeve d, to which gear c is secured. In thisform the direction and speed of rotation is controlled by. moving thefriction-wheel d toward or from the center of the friction-disk e.

In Fig. 5 the hollow shaft is the driving member and is connected bysuitable bevelgears g3f3 with friction-disk e, which in turn drives theshaft a3 through the medium of the adjustable friction-wheel d thereon,and thereby controls the speed of the worms 6"?2, as before. l

In Fig. 6 the casing I) is the driving member and the shaft a5 is thedriven member, and friction-disk e is formed as part of the driver b. Inother respects this form of the apparatus is practically the same asthat shown in Fig. l.

In all of these several forms the principle of operation involved is thesame. The driving and driven members revolve around the same axis. Aplanetary worm-gearing connects said driving and driven members, and avariable-speed device controls the speed of the worm, whereby the speedand direction of motion of the driven member is regulated.

The particular manner of regulating the speed of the worm is not anessential part of the invention, although I prefer the means shown inthe drawings. It is also obvious that other forms of speed-varyingrmechanism than the friction-disk e and the engaging friction-roller dmight be employed without departing from the spirit of the invention,which contemplates, essentially, the provision of a connection betweenthe driving and driven members of means of a positive irreversiblegearing, such as a wormgearing, together with means for varying thespeed of the worm.

It will be noticed that (except when reversing) the worm always turns inthe direction of least resistance. The driving member tending to turnindependently of the driven member exerts a pressure between the teethof IOO IlO

the worm-wheel and the thread of the worm. The angle of the contactingsurfaces of the teeth in this worm-gearing is quite acute, yet it is notsufficient to permit the worm-wheel to drive the worm. It requires,however, a very slight effort on the part of the wormspeed-controllingdevice to keep the worm turning even when the maximum power is beingtransmitted. Therefore the driving effort of the friction-gearing isnecessarily very slight, and it is only when the driven member isreversed in its direction of motion that any considerable driving effortis required on the part of the variable-speed worm-controlling device.

Having thus described my invention, what I claim, and desire to secure,is-

l. A variable-speed and reversing mechanism, comprising a drivingmember, a driven member revolving around the same axis as the drivingmember, non-reversing wormgearing connecting the driving and drivenmembers, and having rotatory motion about the same axis as said members,and means for driving said worm-gearing and varying the speed thereof,whereby the speed and direction of rotation of the driven member areregulated.

2. A variable-speed and reversing mechanism, comprising a drivingmember, a driven member revolving around the same axis as the drivingmember, non-reversing wormgearing connecting the driving and drivenmembers and having rotatory motion about thesame axis as said members,and gearing connecting the driving member and the wormgearing forvarying the speed of the latter, whereby the speed and direction ofrotation of the driven member may be regulated.

3. A variable-speed and reversing mechanism, comprising a drivingmember, a driven member, a worm and a worm-wheel connecting the drivingand driven members for concurrent or independent movement of the saidmembers and having rotatory motion about the same axis as said members,and means for driving the worm-gearing and varying the speed thereoffrom the same to a lower or a higher speed than the driving member,whereby the driven member will remain stationary or have a variablespeed in a forward or a reverse direction imparted to it.

4. A variable-speed and reversing mechanism, comprising a drivingmember, a driven member, a worm and a worm-wheel connecting the drivingand driven members for concurrent or independent movement of saidmembers andhaving rotatory motion about the same axis as said members,and variable-speed friction-gearing driven by the driving member foractuating the worm-gearing at the same speed as, or a lower or higherspeed than that of the driving member, whereby the driven member willremain stationary or be rotated in a forward or a reverse direction atvariable speeds.

5. A variable-speed and reversing mechanism, comprising adriving-shaft,a driven shaft revolving around the same axis as thedriving-shaft, a worm-wheel fast to the drivingshaft, a worm carried bythe driven shaft meshing with said worm-wheel and adapted to rotateabout the latter, and variable-speed gearing for driving said worm,whereby the speed and direction of rotation of the driven shaft areregulated.

6. A variable-speed and reversing mechanism,comprising a driving-shaft,a driven shaft revolving around the same axis as the driving-shaft, aworm-wheel fast on the drivingshaft, a frame on the driven shaft, a wormcarried by said fratrie and meshing with said worm-wheel, afriction-disk driven by said driving-shaft, an adjustable friction-wheeldriven by said disk, and gearing connecting said disk and said worm forvarying the speed of the latter, whereby the driven shaft may be heldstationary or variably rotated in a forward or reverse direction.A

7 A variable-speed and reversing mechanism, comprising a drivingmember,` a driven member, worm-gearing carried by the driving and drivenmembers respectively, and means for driving the worm-gearing and varyingthe speed thereof, whereby the speed and direction of rotation of thedriven member are regulated. v

8. A variable-speed and reversing mechanism, comprising a drivingmember, a driven member, a worm-wheel carried by the driving member, aworm carried by the driven member and meshing with said worm-gear, andmeans for driving the worm and varying the speed thereof, whereby thespeed and direction of rotation of the'driven member are regulated.

In testlmony whereof I aiiix my signature 1n presence of two witnesses.

FAY O. FARWELL. Witnesses:

H. H. BECK, E. F. HEIL.

IOO

